A first-generation antipsychotic
Chlorpromazine
An older 'first-generation' antipsychotic used to treat schizophrenia and other conditions with psychosis, also valued for its calming, sedating effect.
What is Chlorpromazine?
Chlorpromazine is a first-generation (older) antipsychotic medicine used mainly for schizophrenia and other illnesses that cause psychosis. It dampens the activity of dopamine in the brain to ease symptoms such as hallucinations and delusions, and it is also quite sedating. It can cause movement side effects and makes the skin more sensitive to sunlight, so sun protection is advised.
Education and reference only. This is a plain-language guide to Chlorpromazine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Chlorpromazine is one of the oldest antipsychotic medicines and the drug that opened the modern era of treating serious mental illness. In the UK it is used for schizophrenia and other psychotic conditions, and at times for severe agitation, persistent hiccups and nausea. It is markedly sedating, which can be helpful when someone is very distressed or agitated, but means it tends to cause drowsiness. It is taken regularly and works over days to weeks rather than instantly.
How it works
Chlorpromazine blocks dopamine receptors in the brain, which is thought to reduce the hallucinations, delusions and disordered thinking of psychosis. It also blocks several other receptor types — histamine (causing drowsiness), acetylcholine (causing dry mouth and similar effects) and those involved in blood-pressure control (which can cause dizziness on standing). This broad action explains both its calming effect and its wide range of side effects.
Company & origin
Originated / developed by: Rhône-Poulenc.
Synthesised in France by Rhône-Poulenc in the early 1950s, chlorpromazine was the first effective antipsychotic and transformed the treatment of serious mental illness.
What it treats
Conditions Chlorpromazine is used for
Practical use
How to take Chlorpromazine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it regularly as prescribed, at the same times each day, to keep a steady level in the body.
- It can be taken with or without food; taking it with a little food may ease stomach upset.
- Because it is sedating, the largest part of the day's treatment is often taken in the evening.
- Protect your skin from strong sunlight — cover up and use a high-factor sun cream, as the skin burns more easily.
- Do not stop suddenly; if you want to come off it, your prescriber will reduce it gradually.
- If you miss a dose, take it when you remember unless it is nearly time for the next one — never double up.
Weighing it up
Advantages & disadvantages of Chlorpromazine
Advantages
- A long-established medicine with decades of clinical experience behind it.
- Its sedating effect can be helpful when someone is very agitated or distressed.
- Available as a liquid as well as tablets, which helps people who struggle to swallow.
- Inexpensive and widely available.
Disadvantages
- Quite sedating, which can interfere with daytime alertness and driving.
- Can cause movement side effects (stiffness, tremor, restlessness) known as extrapyramidal effects.
- Makes the skin much more sensitive to sunlight, so sunburn is more likely.
- Can lower blood pressure on standing, causing dizziness, and can affect the heart's rhythm.
Practical use
Good to know
It is sedating, so many people find it makes them drowsy, especially early on. It makes the skin much more sensitive to sunlight, so covering up and using sun protection is sensible. It should not be stopped suddenly — the dose is reduced gradually under medical advice — because stopping abruptly can cause withdrawal effects or a return of symptoms.
Who should not take it / use with caution
- People with a reduced level of consciousness or central nervous system depression.
- People with certain heart-rhythm problems or a markedly prolonged QT interval.
- Used with caution in older people, in those with epilepsy, Parkinson's disease, glaucoma or an enlarged prostate, and in significant heart, liver or breathing problems.
- Caution in pregnancy and breastfeeding — the balance of benefit and risk is weighed by the prescriber.
Monitoring
- Review of mental state and side effects, including any movement problems.
- Blood pressure, weight and, over time, blood sugar and lipids.
- An ECG (heart tracing) may be checked, particularly with higher treatment or heart concerns.
Side effects
- Drowsiness, dry mouth, blurred vision, constipation and weight gain.
- Dizziness on standing because of a drop in blood pressure.
- Movement effects such as stiffness, tremor, restlessness or slowed movement.
- Increased sensitivity of the skin to sunlight, and sometimes a greyish skin tint with long-term use.
- Less commonly, effects on heart rhythm (QT prolongation) and raised prolactin.
- Very rarely, a serious reaction called neuroleptic malignant syndrome can occur (high fever, muscle stiffness, confusion and a fast heartbeat) — this is a medical emergency, seek urgent help.
Key interactions
- Other sedating medicines and alcohol add to drowsiness.
- Other medicines that can affect heart rhythm (QT interval) increase the risk when combined.
- Medicines for Parkinson's disease may work less well alongside it.
- Medicines that lower blood pressure can increase dizziness on standing.
Available as: Tablets and an oral solution; an injection is also used in hospital settings.
Answers
Chlorpromazine: frequently asked questions
Will chlorpromazine make me drowsy?
Often yes, especially when you first start. The drowsiness usually eases as your body adjusts, but tell your prescriber if it is troublesome.
Why do I need to be careful in the sun?
Chlorpromazine makes the skin more sensitive to sunlight, so you can burn more easily. Cover up and use a high-factor sun cream when outdoors.
Can I stop taking it once I feel better?
Do not stop suddenly. Symptoms can return and you may get withdrawal effects. Your prescriber will lower the dose gradually if you are coming off it.
Does it work straight away?
Some calming effect can be felt early because it is sedating, but the antipsychotic benefit builds over days to weeks of regular treatment.
Is chlorpromazine still used today?
Yes, though newer antipsychotics are often preferred. It remains useful, particularly when its sedating effect is helpful or for conditions such as severe hiccups and nausea.
The wider class
About Antipsychotics
Chlorpromazine belongs to the antipsychotics class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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